The present disclosure is directed to minimally invasive cardiac procedures. More specifically, the disclosure provides a device and method for accurate local access to the pericardial space with reduced risk of injury to the myocardium and associated coronary vessels.
Knowledge of the pericardium (pericardial sac) dates back to the time of Galen (129-200 A.D.) the Greek physician and anatomist who created the term xe2x80x9cpericardium.xe2x80x9d The pericardium (pericardial sac) is a conical membranous sac in which the heart and the commencement of the great vessels are contained. Gray""s Anatomy (1977 ed.) pp. 457-460. The pericardium is fluid-filled and functions to prevent dilation of the chambers of the heart, lubricates the surfaces of the heart, and maintains the heart in a fixed geometric position. It also provides a barrier to the spread of infection from adjacent structures in the chest cavity and prevents surrounding tissue(s) from adhering to the heart. The space between the pericardium and the heart, known as the pericardial space, is normally small in volume and includes the fluid therein. It has been reported by others that when fluid is injected into the pericardial space it accumulates in the atrioventricular and interventricular grooves, but not over the ventricular surfaces. See, Shabetai R, xe2x80x9cPericardial and Cardiac Pressure,xe2x80x9d in Circulation, 77:1 (1988).
Pericardiocentesis, or puncture of the pericardium, heretofore has been performed for: 1) diagnosis of pericardial disease(s) by study of the pericardial fluid; 2) withdrawal of pericardial fluid for the treatment of acute cardiac tamponade; and 3) infusion of therapeutic agents for the treatment of malignant effusion or tumors. Thus, at present, intrapericardial injection of drugs is clinically limited to the treatment of abnormal pericardial conditions and diseases, such as malignant or loculated pericardial effusions and tumors. Drugs that have been injected into the pericardial space include antibiotic (sclerosing) agents, such as tetracycline and bleomycin or fibrinolytic agents such as streptokinase.
Intrapericardial drug delivery has not been clinically utilized for heart-specific treatments where pericardial pathology is normal, because the pericardial space is normally small and very difficult to access without invasive surgery or risk of cardiac injury by standard needle pericardiocentesis techniques. Normally, pericardiocentesis procedures are carried out by highly specialized, personnel in the cardiac catheterization laboratory of medical facilities, assisted by fluoroscopy and electrocardiogram monitoring equipment. Electrocardiographic monitoring of pericardiocentesis, using the pericardial needle as an electrode is commonly employed, as disclosed in Bishop L. H., et al., xe2x80x9cThe Electrocardiogram as a Safeguard in Pericardiocentesis,xe2x80x9d in JMA, 162:264 (1956), and Neill J. R., et al., xe2x80x9cA Pericardiocentesis Electrode,xe2x80x9d in The New England Journal of Medicine, 264:711 (1961); Gotsman M. S., et al. xe2x80x9cA Pericardiocentesis Electrode Needle,xe2x80x9d in Br. Heart J., 28:566 (1966); and Kerber R. E., et al., xe2x80x9cElectrocardiographic Indications of Atrial Puncture During Pericardiocentesis,xe2x80x9d in The New England Journal of Medicine, 282:1142 (1970). An echocardiographic transducer with a central lumen has also been used to guide the pericardiocentesis needle as reported in Goldberg B. B., et al., xe2x80x9cUltrasonically Guided Pericardiocentesis,xe2x80x9d in Amer. J. Cardiol., 31:490 (1973).
However, there are complications associated with needle pericardiocentesis. These complications include laceration of a coronary artery or the right ventricle, perforation of the right atrium or ventricle, puncture of the stomach or colon, pneumothorax, arrhythmia, tamponade, hypertension, ventricular fibrillation, and death. Complication rates for needle pericardiocentesis are increased in situations where the pericardial space and fluid effusion volume is small (i.e., the pericardial size is more like normal and not abnormally distended by the accumulation of fluid, e.g., blood).
U.S. Pat. No. 5,071,428 (Chin et al.) discloses a method and apparatus for accessing the pericardial space for the insertion of implantable defibrillation leads. This method requires gripping the pericardium with a forceps device and cutting the pericardium with a scalpel (pericardiotomy) under direct vision through a subxiphoid surgical incision.
Uchida Y., et al., xe2x80x9cAngiogenic Therapy of acute Myocardial Infarction by Intrapericardial Injection of Basic Fibroblast Growth Factor and Heparin Sulfate,xe2x80x9d in Circulation AHA Abstracts (1994), reported a method for the intrapericardial injection of angiogenic agents. While not described in detail, this method generally involved the percutaneous transcatheter bolus injection of drugs into the pericardial cavity via the right atrium. A major drawback of this method is that the right atrial wall is crossed, that could lead to bleeding into the pericardial space. In addition, the method involved the bolus injection of drugs rather than long-term.delivery via a catheter of controlled release material.
U.S. Pat. No. 4,991,578 (Cohen) discloses an apparatus for accessing the pericardial space for placement of defibrillation electrodes. The apparatus uses suction to xe2x80x9cpullxe2x80x9d the pericardium against a perforating needle housed in an outer catheter, thus impaling the pericardium on the needle (col. 15, lines 54-57). One of the stated problems with the apparatus is loss of suction. Col. 15, lines 4-5. A solution to the loss of suction proposed in the patent is to apply suction to pull the pericardium into the lumen of the catheter, apply a wire suture to stabilize the catheter tip and subsequently advance a piercing needle into the pericardium sutured to the catheter. In addition to other disadvantages the added step of suturing in this method is undesirable.
Another method for intrapericardial injection of agents is performed by a device, available under the name PerDUCER(trademark) pericardial access device, available from Comedicus Incorporated, 3839 Central Avenue, NE, Columbia Heights, Minn. 55431. This device uses suction to create a lifted section of the pericardium, called a xe2x80x9cbleb.xe2x80x9d Specifically, the bleb is secured to an elongate access device by a suction force exerted through a side wall port that is in a plane parallel to the longitudinal access of the device. Once formed, the bleb is punctured by a needle of limited travel that penetrates the bleb in a direction substantially tangential to the epicardial surface of the heart. While creating a bleb by suction through a side wall port combined with a tangential needle approach to the bleb can reduce the chance of puncturing or lacerating the myocardium, accurately penetrating the pericardium at a desired location may be difficult due to the motion of the heart during normal cardiac contraction relative to the orientation of the axial dimension of the a device.
Accordingly, there is a need for an accurate system for localized penetration of the pericardium which has low risk of causing penetration or laceration of the myocardium. Moreover, there is a need to effectively penetrate the pericardium without the chance of loss of vacuum and repeated attempts to effect penetration.
The present invention provides a device and method for safe access to the pericardial space without injury to the heart, in order to aspirate fluids directly from or to directly deliver fluids, i.e., therapeutic drugs, to the heart muscle or associated vasculature. With such safe access to the heart, complications from contacting the heart muscle are greatly reduced and nearly eliminated. Additionally, by directly delivering drugs to the heart muscle via the pericardium (pericardial sac), side affects associated with drug delivery by conventional administration methods, i.e., oral or injection, can be reduced, such that reduced dosages are needed to achieve the desired effect of a specific drug. Moreover, the present method for direct delivery of a drug provides for a wider range of drugs to be used.
A pericardial access device according to the invention includes a penetrating body that is axially mobile within the lumen of a guide tube. The guide tube has a proximal end for handling and operating the pericardial access device and a distal end having a distal port opening into the lumen of the guide tube. Within the distal end of the guide tube lumen there is an axially directed shoulder. The axially directed shoulder can be continuous around the circumference of the lumen or can be intermittent.
According to the invention, a suction or aspiration force is applied to the lumen of the guide tube to form a bleb of pericardial tissue in the distal lumen of the guide tube. That is, the suction draws the bleb of pericardium into the distal port such that it passes through the lumen opening between the axial shoulders and extends proximal thereto. A penetrating body having a piercing tip is axially mobile within the guide tube lumen. As the piercing tip of the penetrating body is advanced distally to pierce into the pericardial bleb, the bleb mushrooms outward forming edges which are buttressed by the shoulders. Thus, the shoulders prevent the bleb from moving away from the distal end of the guide tube and prevents breakage of the vacuum seal that maintains the bleb in a fixed location for accurate pericardial penetration. Subsequently, a guide wire can be passed through a lumen of the penetrating body, the pericardial access device removed and a material transport tube passed over the guide wire into the pericardial space for removal of fluid or delivery of materials therein.
At the proximal end of the pericardial access device, the handle region can include a vacuum inlet assembly for connecting an aspiration source to the device. In addition, the handle region can include a limiting mechanism for limiting the axial mobility of the penetrating body distally.
In some embodiments, a pericardial access device can include an exterior sheath having a reversibly sealed distal end to prevent fat, fascia, or other material from entering the distal end of the pericardial access device during placement.
The invention also provides a method for using a pericardial access device for accessing the pericardial space.